This invention relates to a multiple cell inflation element, such as an air mattress, air cushion or the like.
In multiple cell air mattresses and the like, it is advantageous to have a facility whereby the individual cell can be provided with different inflation pressures. For example, it is advantageous for the cells which receive the maximum load to be able to reduce pressure relative to the cells which are not so heavily loaded.
Earlier U.S. Pat. No. 4,646,373 discloses a multiple cell inflation element in which communication can be selectively provided between the respective cells when the element is inflated so that those cells which are under the maximum load can transfer air to the cells which are not as heavily loaded. In this arrangement, each cell communicates with a common inflation duct through an inflation passage. A valve element located in the cell extends into the inflation passage and all of the valve elements are connected to a common valve actuator. The valve actuator itself takes the form of an inflatable tube positioned within the inflation duct. When the tube is deflated, the various valve elements serve to close the inflation passages of the individual cells and prevent communication between the cells. When the tube is inflated, however, the valve elements are shifted to open the respective passages and allow communication between the cells for the purpose of distributing uneven loads as described above.